White Semicircle Meters

The following is the command line version of the code in "cppdemo/whitesemicirclemeter". The MFC version of the code is in "mfcdemo/mfcdemo". The Qt Widgets version of the code is in "qtdemo/qtdemo". The QML/Qt Quick version of the code is in "qmldemo/qmldemo".
#include "chartdir.h"

void createChart(int chartIndex, const char *filename)
{
    // The value to display on the meter
    double value = 72.55;

    // Create an AngularMeter object of size 300 x 180 pixels with transparent background
    AngularMeter* m = new AngularMeter(300, 180, Chart::Transparent);

    // Set the default text and line colors to very dark grey (0x222222)
    m->setColor(Chart::TextColor, 0x222222);
    m->setColor(Chart::LineColor, 0x222222);

    // Center at (150, 150), scale radius = 128 pixels, scale angle -90 to +90 degrees
    m->setMeter(150, 150, 128, -90, 90);

    // Gradient color for the border to make it silver-like
    double ringGradient[] = {1, 0x999999, 0.5, 0xdddddd, 0, 0xf8f8f8, -0.5, 0xdddddd, -1, 0x999999};
    const int ringGradient_size = (int)(sizeof(ringGradient)/sizeof(*ringGradient));

    // Background gradient color from white (0xffffff) at the center to light grey (0xdddddd) at the
    // border
    double bgGradient[] = {0, 0xffffff, 0.75, 0xeeeeee, 1, 0xdddddd};
    const int bgGradient_size = (int)(sizeof(bgGradient)/sizeof(*bgGradient));

    // Add a scale background of 148 pixels radius using the gradient background, with a 10 pixel
    // thick silver border
    m->addScaleBackground(148, m->relativeRadialGradient(DoubleArray(bgGradient, bgGradient_size),
        148), 10, m->relativeLinearGradient(DoubleArray(ringGradient, ringGradient_size), 45, 148));

    // Add a 1 pixel light grey (0xbbbbbb) line at the inner edge of the thick silver border (radius
    // = 138) to enhance its contrast with the background gradient
    m->addScaleBackground(138, Chart::Transparent, 1, 0xbbbbbb);

    // Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10 units, and micro
    // tick every 5 units
    m->setScale(0, 100, 20, 10, 5);

    // Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    // 16/16/10 pixels pointing inwards, and their widths to 2/1/1 pixels.
    m->setLabelStyle("Arial Italic", 16);
    m->setTickLength(-16, -16, -10);
    m->setLineWidth(0, 2, 1, 1);

    // Demostrate different types of color scales and putting them at different positions
    double smoothColorScale[] = {0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100,
        0xff0000};
    const int smoothColorScale_size = (int)(sizeof(smoothColorScale)/sizeof(*smoothColorScale));
    double stepColorScale[] = {0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 100};
    const int stepColorScale_size = (int)(sizeof(stepColorScale)/sizeof(*stepColorScale));
    double highLowColorScale[] = {0, 0x00ff00, 70, Chart::Transparent, 100, 0xff0000};
    const int highLowColorScale_size = (int)(sizeof(highLowColorScale)/sizeof(*highLowColorScale));

    if (chartIndex == 0) {
        // Add the smooth color scale at the default position
        m->addColorScale(DoubleArray(smoothColorScale, smoothColorScale_size));
    } else if (chartIndex == 1) {
        // Add the smooth color scale starting at radius 128 with zero width and ending at radius
        // 128 with 16 pixels inner width
        m->addColorScale(DoubleArray(smoothColorScale, smoothColorScale_size), 128, 0, 128, -16);
    } else if (chartIndex == 2) {
        // Add the smooth color scale starting at radius 70 with zero width and ending at radius 60
        // with 20 pixels outer width
        m->addColorScale(DoubleArray(smoothColorScale, smoothColorScale_size), 70, 0, 60, 20);
    } else if (chartIndex == 3) {
        // Add the high/low color scale at the default position
        m->addColorScale(DoubleArray(highLowColorScale, highLowColorScale_size));
    } else if (chartIndex == 4) {
        // Add the step color scale at the default position
        m->addColorScale(DoubleArray(stepColorScale, stepColorScale_size));
    } else {
        // Add the smooth color scale at radius 60 with 15 pixels outer width
        m->addColorScale(DoubleArray(smoothColorScale, smoothColorScale_size), 60, 15);
    }

    // Add a text label centered at (150, 125) with 15pt Arial Italic font
    m->addText(150, 125, "CPU", "Arial Italic", 15, Chart::TextColor, Chart::BottomCenter);

    // Add a red (0xff0000) pointer at the specified value
    m->addPointer2(value, 0xff0000);

    // Output the chart
    m->makeChart(filename);

    //free up resources
    delete m;

}

int main(int argc, char *argv[])
{
    createChart(0, "whitesemicirclemeter0.png");
    createChart(1, "whitesemicirclemeter1.png");
    createChart(2, "whitesemicirclemeter2.png");
    createChart(3, "whitesemicirclemeter3.png");
    createChart(4, "whitesemicirclemeter4.png");
    createChart(5, "whitesemicirclemeter5.png");
    return 0;
}